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From: Malcolm Priestley <tvboxspy@gmail.com>
To: linux-media@vger.kernel.org, simon.farnsworth@onelan.com
Subject: Re: Problems tuning PAL-D with a Hauppauge HVR-1110 (TDA18271 tuner) - workaround hack included
Date: Fri, 30 Sep 2011 19:05:14 +0100	[thread overview]
Message-ID: <4E8604DA.2070008@gmail.com> (raw)
In-Reply-To: <201109281350.52099.simon.farnsworth@onelan.com>

On 28/09/11 13:50, Simon Farnsworth wrote:
> (note - the CC list is everyone over 50% certainty from get_maintainer.pl)
>
> I'm having problems getting a Hauppauge HVR-1110 card to successfully
> tune PAL-D at 85.250 MHz vision frequency; by experimentation, I've
> determined that the tda18271 is tuning to a frequency 1.25 MHz lower
> than the vision frequency I've requested, so the following workaround
> "fixes" it for me.

Are you sure the transmitter concerned doesn't have a VSB filter for an 
adjacent DVB-T digital transmitter?

VSB fitlers have been used on UK(PAL-I) transmitters for some time.

From
downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP023.pdf

"To avoid the likelihood of PAL-I interference to DTT transmissions, the 
proposal is to use a System B/G VSB filter which provides at least 30 dB 
of sideband attenuation at 1.4 MHz below the vision carrier. It is also 
necessary to reduce the image sidebands resulting from transmitter 
non-linearity, and the method is to fit a high-order bandpass filter at 
the transmitter output. Typically, the overall sideband response will be 
-2 dB at (fv - 0.75) MHz and -20 dB at (fv - 1.25) MHz, where fv is the 
frequency of the vision carrier."



  parent reply	other threads:[~2011-09-30 18:05 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-28 12:50 Problems tuning PAL-D with a Hauppauge HVR-1110 (TDA18271 tuner) - workaround hack included Simon Farnsworth
2011-09-28 14:20 ` Devin Heitmueller
2011-09-28 14:27   ` Simon Farnsworth
2011-09-30 10:48 ` Mauro Carvalho Chehab
2011-09-30 11:03   ` Simon Farnsworth
2011-09-30 11:59     ` Mauro Carvalho Chehab
2011-09-30 14:43       ` Devin Heitmueller
2011-09-30 11:11   ` Simon Farnsworth
2011-09-30 13:35     ` Mauro Carvalho Chehab
2011-09-30 18:05 ` Malcolm Priestley [this message]
2011-10-03  8:56   ` Simon Farnsworth
2011-09-30 19:37 ` Steven Toth
2011-09-30 21:25   ` Andy Walls
2011-10-03  8:57     ` Simon Farnsworth

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